On Tue, Aug 26, 2008 at 2:07 AM, Stan Schymanski <[EMAIL PROTECTED]> wrote:
>
> Dear William,
>
> On Aug 25, 6:48 pm, "William Stein" <[EMAIL PROTECTED]> wrote:
>
>> If you call _fast_float_ as illustrated below on your functions, find_* will
>> work, and also be much much faster:
>>
>> sage: find_maximum_on_interval((-x^2)._fast_float_(x),-1,1)
>> (-7.7037197775489434e-34, -2.77555756156e-17)
>> sage: find_minimum_on_interval((-x^2)._fast_float_(x),-1,1)
>> (-0.99999992595132459, -0.999999962976)
>>
>> find_* doesn't do this already since (1) _fast_float_ was written
>> after find_*, and (2) nobody has had the time to change find_*
>> to use _fast_float_.
>
> That's amazing, thank you! I didn't find any information about the
> _fast_float_. Can it be used for other purposes, too?
Yes. It takes any polynomial or symbolic expression and turns
it into a very fast callable function that has input and output floats.
It should get used automatically by functions like find_min* but
we haven't pushed this through enough yet.
I've made fixing this to be automatic trac ticket #3955:
http://trac.sagemath.org/sage_trac/ticket/3955
William
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